In the prior art, different welding auxiliary joining parts are known. Frequently, the shape of the known welding auxiliary joining parts varies depending on the setting method and the subsequent welding method and depending on the materials to be joined to each other.
In DE 10 2010 020 569, a welding auxiliary joining part is pressed into a component made of non-weldable material. This welding auxiliary joining part is flattened on both sides to facilitate in this way the abutting of a welding electrode. When the welding auxiliary joining part is pressed or punched in, a generated material slug must be removed, which causes an avoidable procedural effort. Due to this procedure, the combination of the setting process of the welding auxiliary joining part with the subsequent welding process is also made more difficult.
A similar fastening of a welding auxiliary joining part is disclosed in DE 100 15 713 A1. Here, a rivet is inserted having a T-shape or a double-T-shape after the setting. The here set welding auxiliary joining parts provide advantageous contact points for, for example, resistance welding, but require at the same time a complex fastening of the welding auxiliary joining part and removing of a slug during the setting method.
In DE 100 60 390 A1, a known punch riveting method takes place, wherein the punch and the die also act as welding electrodes. The electric current flowing through the rivet serves on the one hand for the heating of the components to support the joining process. On the other hand, the electric current is increased so much that also a welded connection between the rivet and the component made of weldable material is producible.
In DE 10 2004 025 492, also a known setting method is used in which the punch and the die form electrodes for resistance welding at the same time. As a first component made of a non-weldable material is to be joined to a second component made of a weldable material, the welding starts at the earliest upon contact between the welding auxiliary joining part and the second component. Since the welding auxiliary joining part is pressed comparatively slowly into the components, the welding takes place under combined electrical and mechanical loads on the components. Thus, a combined setting-welding method is used, at which a connection between the first and the second component is already established solely due to the setting method. This requires that the components to be connected are always commonly positioned between the punch and the die. Thus, for example, an equipping of the first component with the welding auxiliary joining part prior to the welding process is impossible. Further, the welding auxiliary joining parts according to the method described herein have different cutting and tip geometries. Depending on the cutting or tip geometry as well as the number of tips being present at a welding auxiliary joining part, different welding zones evolve. The different welding zones influence the nature and extent of the welding connection between the welding auxiliary joining part and the second component.
DE 10 2007 036 416 describes a welding auxiliary joining part in the manner of a nail. By means of the tip of the welding auxiliary joining part it can be set into an aluminum sheet, so that the tip of the welding auxiliary joining part can be subsequently used as welding projection in resistance welding. The tip, however, has the disadvantage that first, only an area selectively limited to the tip of the welding auxiliary joining part is flown through by an electric welding current to form a welding zone. Only when the tip is piecewise melting, the weld zone and thus the connection area between the welding auxiliary joining part and the second component gets larger or increases. This procedure is time-consuming and has a negative impact on the overall time of the connection method.
In DE 10 2012 018 866, bolts are being set into an at least first component made of a poorly-weldable material by means of combined mechanical and thermal loads. Thereby, the thermal loads, generated for example by a current flowing in the bolt, cause the setting process. In combination or subsequently thereto, a welding of the bolt to a second component consisting of weldable material occurs. In preparation of the welding procedure, the tip of the bolt is deformed at the anvil.
DE 10 2012 010 870 describes a two-staged connection method by means of a bolt. First, the bolt is set into a first component and compressed at an anvil or a die. The deformation of the bolt tip related thereto is to prepare the subsequent welding of the deformed bolt to a component made of a weldable material. Thereby, the bolt tip is deformed at differently-shaped dies to produce a welding head adapted to fit the subsequent welding process. In this context, it has been proven to be disadvantageous that, during the setting of the bolt into the first component, the material of the first component is not completely displaced from the deformed tip portion of the bolt. This can lead to negative effects in the subsequent welding procedure as the material of the first component is poorly weldable and hinders the production of a welded joint.
It is therefore an object of at least certain implementations of the present invention to optimize the upstream setting method of a welding auxiliary joining part compared to the prior art, in order to reduce the procedural shortcomings during the subsequent welding.